The best time to buy long term disability insurance is when you are healthy and have a stable income. It's important to purchase this type of insurance before any health issues arise, as pre-existing conditions may be excluded from coverage or result in higher premiums. Additionally, it's advisable to consider buying long term disability insurance early in your career when your income potential is at its peak. This ensures that you secure coverage based on your current income level, which will be used to determine your benefit amount in the event of a disability. Waiting too long to purchase long term disability insurance may result in higher premiums or limited coverage options. It's always a good idea to consult with an insurance specialist who can provide personalized advice based on your specific needs and circumstances.